Network traffic policies are implemented to manage communications network performance, suppress malicious activities such as junk e-mail generation and propagation, ensure adherence to contractual obligations, and the like. The network traffic policies need to be periodically tested or verified to assure service quality.
Brix™ system manufactured by EXFO Inc. having headquarters in Quebec City, Quebec, Canada, includes a plurality of hardware devices called “Brix Verifiers”, connected to unused router and switch ports throughout the network, and controlled via software from a remote location. The Brix Verifiers can analyze Voice over IP (VoIP), video, and data streams in the network, gathering network statistics to assure service quality (EXFO Brix System Spec Sheet, October 2010). Detrimentally, Brix Verifiers represent a substantial additional cost for a network operator, making widespread deployment of these devices throughout wide-area networks prohibitively expensive.
Phaal in U.S. Pat. No. 5,315,580 discloses a network monitoring system including a plurality of monitoring devices and a central measurement station connected to free ports of routers in a network. In operation, the monitoring devices sample packets from time to time in a pseudo random manner, and transmit data from the sampled packets to the measurement station for processing and analysis. The random sampling of data packets relaxes the processing power requirement and cost of the monitoring devices and the central measurement station, thus making the overall system less expensive, although the pseudo-random sampling results in only approximate evaluation of the network performance. Furthermore, the monitoring devices of Phaal and Brix Verifiers of the Brix system are not inline devices, so it is not feasible to deploy them without consuming additional router/switch ports.
Telchemy Inc., Duluth, Ga., USA, provides software test agents, which can run on endpoint network devices such as cell phones. A specialized software, running on a dedicated or shared remote computer, presents a real-time dashboard of quality metrics and diagnostic information.
Clark discloses similar systems in US Patent Application Publication 2007/0263775, and in U.S. Pat. No. 7,058,048. In the Clark systems, Voice Quality monitor software agents are installed at endpoints (VoIP terminals) of a communications network. The software agents analyze the arriving VoIP packets to determine VoIP signal quality parameters such as latency and jitter, and generate Quality of Service (QoS) reports. A dedicated Service Management System, connected to the network, collects the QoS reports from the individual software agents, and presents the reports to a network administrator in a summary format.
Detrimentally, the Telchemy system and the Clark systems require the endpoint network devices to be pre-programmed to respond to the test packets generated by the test system software. This consumes network resources, and makes the software agents dependent on the particular vendor's platforms. Furthermore, the Telchemy system and the Clark systems described above are dedicated mostly to testing of VoIP data packets.
Hedayat et al. in U.S. Pat. Nos. 7,840,670 and 7,454,494 disclose a system for testing performance of packet-based networks. In the diagnostic system of Hedayat et al., diagnostic data packets are generated and sent by a diagnostic system coupled to the network under test. The diagnostic data packets travel along a communications path, which includes a plurality of routers. Each router along the path is programmed to send to the diagnostic system response packets that include timestamp, address of the router, etc. The diagnostic system analyzes the response packets from the routers along the path, thereby determining packet jitter, packet loss, and the like. Detrimentally, the diagnostic system of Hedayat et al. relies on a specific router capability or behaviour, and thus has a limited capability of testing specific locations of the network.